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Nitric oxide stimulates the erythrocyte for ascorbate recycling.
Maria Stefania Spagnuolo1, Alessandro Carlucci, Luisa Cigliano
1Dipartimento delle Scienze Biologiche, Università di Napoli Federico II, via Mezzocannone 8, 80134 Napoli, Italy.
Nitric Oxide : Biology and Chemistry
|November 19, 2005
Summary
Nitric oxide (NO) stimulates red blood cells to recycle vitamin C (Ascorbate). This NO-driven ascorbate recycling may prevent its depletion in circulation, revealing a novel NO function.
Area of Science:
- Biochemistry
- Physiology
- Redox Biology
Background:
- S-Nitrosothiols serve as nitric oxide (NO) reservoirs, releasing NO upon ascorbate (Asc) stimulation.
- Erythrocytes possess the capacity to regenerate Asc from its oxidized forms, preserving this vital antioxidant.
Purpose of the Study:
- To investigate the impact of NO, superoxide, and peroxynitrite donors on Asc recycling within erythrocytes.
- To elucidate the novel role of NO in modulating Asc regeneration in red blood cells.
Main Methods:
- Utilized NO donors (SpNONOate, GSNO), superoxide donor (KO2), and peroxynitrite donor (SIN-1) to treat erythrocytes.
- Measured Asc production and recycling rates under varying conditions.
- Assessed the influence of temperature and pH on Asc recycling.
Main Results:
- Nitric oxide (NO) significantly stimulated Asc recycling in erythrocytes.
- Superoxide and peroxynitrite inhibited Asc recycling.
- Ascorbate recycling by erythrocytes was demonstrably influenced by temperature and pH, both with and without NO presence.
- Confirmed NO's stimulatory effect using S-nitrosoglutathione (GSNO).
Conclusions:
- Nitric oxide exhibits a novel function in stimulating erythrocyte Asc recycling.
- This NO-mediated Asc regeneration may prevent antioxidant depletion in circulation.
- A potential positive feedback loop between Asc and S-nitrosothiols could enhance Asc and NO production.